On Thu, 2019-04-04 at 16:43 +0800, Ming Lei wrote:
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index b512ba0cb359..41c12d9008b7 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -3224,8 +3224,11 @@ static void __blk_mq_update_nr_hw_queues(struct
> blk_mq_tag_set *set,
> if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)
> return;
>
> - list_for_each_entry(q, &set->tag_list, tag_set_list)
> + list_for_each_entry(q, &set->tag_list, tag_set_list) {
> blk_mq_freeze_queue(q);
> + blk_mq_quiesce_queue(q);
> + blk_sync_queue(q);
> + }
> /*
> * Sync with blk_mq_queue_tag_busy_iter.
> */
> @@ -3269,8 +3272,10 @@ static void __blk_mq_update_nr_hw_queues(struct
> blk_mq_tag_set *set,
> list_for_each_entry(q, &set->tag_list, tag_set_list)
> blk_mq_elv_switch_back(&head, q);
>
> - list_for_each_entry(q, &set->tag_list, tag_set_list)
> + list_for_each_entry(q, &set->tag_list, tag_set_list) {
> + blk_mq_unquiesce_queue(q);
> blk_mq_unfreeze_queue(q);
> + }
> }
>
> void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
Are you sure this patch is sufficient? What prevents that blk_mq_run_hw_queues()
gets called after the blk_mq_quiesce() and blk_sync_queue() calls have finished
and before the queue is unfrozen?
Bart.
